RESTRUCTURING, IMPAIRMENT AND OTHER CHARGES: Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2015
Restructuring Cost and Reserve [Line Items]
Restructuring charges and adjustments	$ 3,430	$ 7,745	$ 2,746
Restructuring reserve	6,200
Gains Losses And Other Items Net
Restructuring Cost and Reserve [Line Items]
Restructuring charges and adjustments	3,400			$ 3,000
Restructuring Activity 2019 | Gains Losses And Other Items Net
Restructuring Cost and Reserve [Line Items]
Restructuring charges and adjustments		7,700
Restructuring Activity 2018 | Gains Losses And Other Items Net
Restructuring Cost and Reserve [Line Items]
Restructuring charges and adjustments			2,700
Restructuring Activity 2015 | Gains Losses And Other Items Net
Restructuring Cost and Reserve [Line Items]
Restructuring charges and adjustments					$ 9,300
Employee Severance | Restructuring Activity 2018 | Gains Losses And Other Items Net
Restructuring Cost and Reserve [Line Items]
Restructuring charges and adjustments			200
Employee Severance | Restructuring Activity 2015 | Gains Losses And Other Items Net
Restructuring Cost and Reserve [Line Items]
Restructuring charges and adjustments					2,600
Termination Of Associates | Gains Losses And Other Items Net
Restructuring Cost and Reserve [Line Items]
Restructuring charges and adjustments	1,100			3,000
Termination Of Associates | Restructuring Activity 2019 | Gains Losses And Other Items Net
Restructuring Cost and Reserve [Line Items]
Restructuring charges and adjustments		800
Termination Of Associates | Restructuring Activity 2018 | Gains Losses And Other Items Net
Restructuring Cost and Reserve [Line Items]
Restructuring charges and adjustments			$ 2,500
Leased office facilities | Gains Losses And Other Items Net
Restructuring Cost and Reserve [Line Items]
Restructuring charges and adjustments				1,500
Adjustments to estimates related to the fiscal 2015 lease accruals | Gains Losses And Other Items Net
Restructuring Cost and Reserve [Line Items]
Restructuring charges and adjustments				$ 1,500
Contract Termination | Restructuring Activity 2015 | Gains Losses And Other Items Net
Restructuring Cost and Reserve [Line Items]
Restructuring charges and adjustments					4,700
Leasehold Improvement Write Offs | Restructuring Activity 2019 | Gains Losses And Other Items Net
Restructuring Cost and Reserve [Line Items]
Restructuring charges and adjustments		800
Leasehold Improvement Write Offs | Restructuring Activity 2015 | Gains Losses And Other Items Net
Restructuring Cost and Reserve [Line Items]
Restructuring charges and adjustments					$ 2,000
Asia-Pacific | Employee Severance
Restructuring Cost and Reserve [Line Items]
Restructuring charges and adjustments	600
Restructuring reserve	200
United States | Employee Severance
Restructuring Cost and Reserve [Line Items]
Restructuring charges and adjustments	1,700
United States Australia China And Europe | Employee Severance | Restructuring Activity 2019
Restructuring Cost and Reserve [Line Items]
Restructuring charges and adjustments		$ 6,100
United States Australia China And Europe | Employee Severance | Restructuring Activity 2015
Restructuring Cost and Reserve [Line Items]
Restructuring reserve	$ 200